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My wife's ResMed unit has an optional DC-to-DC power supply with a cigarette lighter connector. We purchased a deep-cycle lead acid battery, battery box, charge
by EvanAnderson 8y ago
My wife's ResMed unit has an optional DC-to-DC power supply with a cigarette lighter connector. We purchased a deep-cycle lead acid battery, battery box, charger / desulfator, and various cables and came up with a nice modular system that doubles as both a backup for a power outage and something we can take camping. It stays plugged-in at home under her bedside table and is easy to swap-in if need be.
She forgoes the humidifier on camping trips, which tremendously helps the battery life. If we did camping trips longer than 3-day weekends I'd probably also put together a solar charging rig, but as it stands she can get 3 or 4 nights out of our current rig with enough reserve to go a couple more nights if we needed to.
The most costly part was the ResMed DC-to-DC power supply (at about $100, if memory serves). I felt a lot better about using that supply than an inverter and it's more efficient, too.
- amluto 8y agoHow long ago was this? These days, I would expect a LiFePO4 system to be comparably priced (especially if you consider that it should survive considerably more cycles than a lead-acid battery) and smaller and lighter to boot. M
- EvanAnderson 8y agoWe did this last summer. The 35AH battery we're using cost $64 at the time. I probably ended up spending more per cycle, but I'm guessing my out-of-pocket at the time was lower (and it was kind of a gamble as to how much we'd actually use the rig).
- vvanders 8y agoThe other thing to consider is that lead batteries don't mind being floated at max capacity for long periods of time. Lithium batteries like to stay closer to 90%, unfortunately most chargers just blindly charge to 100%.